This invention relates to linear direct-current (DC) permanent magnet motors.
Heretofore, linear motors have been presented having a permanent magnet field member that moves rectilinearly over a linear bed of overlapping, stationary (relative to the field member) armature coils wound about teeth of an elongated slotted core, each coil being energized in sequence via commutator/brush contacts as the field member passes overhead. Movement of the field member relative to the armature is caused by interaction of the energized coils with the magnetic field of the permanent magnet member. An example of such a motor is disclosed in U.S. Pat. No. 4,369,383 by Langley.
Such motors have traditionally had overheating problems and commutator/brush contact burn problems, and so various ways have been devised to reduce the heat generation and/or dissipate the heat generated, particularly heat in the commutators.
For example, U.S. Pat. No. 4,906,878 by Twealfhoven et al. presents a linear DC motor as described above having a network of fluid coolant manifolds strategically placed to remove heat.
This invention was conceived and designed to, among other things, distribute current in a more even and balanced fashion which results in less concentrated heat generation, particularly in the commutators, giving motors built according to this invention improved heat damage resistance. As will be explained, this invention also provides basically two motors in one because of separately controllable armature coils.
Other attributes and advantages of this invention will become apparent upon a reading of the text hereinafter.